Essex Red Data List commentNationally important populations in the East Thames Corridor, but highly threatened.

Species textThis bumblebee is a national BAP species on the basis of major declines across Britain, especially inland. Although not included in Falk (1991a) it should now be viewed as Nationally Scarce. The East Thames Corridor region currently supports one of the most important remaining metapopulations in the UK, but many sites are already lost or under direct threat of development. It is considered Vulnerable in the county. Bumblebee populations appear to operate at a landscape scale and it is probable that viable individual populations require minimum ranges of between ten to twenty sq. km of good matrix habitat within farmland (Edwards, 1998). The distribution map here needs to be interpreted with the understanding that recent sites have been lost and many more are under huge development threats

Forage areas need to be considered separately for queens and workers. The queens require nectar resources early in the season after their long winter hibernation to build up their reserves. They then need pollen resources for stocking cells in newly established nests to enable the first workers to develop. Workers also require nectar and pollen resources both for their own sustenance and to stock the developing nest. It appears that areas of fairly tall, open flower-rich grasslands providing areas of abundant forage are required to support populations of Bombus humilis, but it is more able to utilise suitable small areas within a landscape than Shrill Carder Bee, another bumblebee with a nationally important metapopulation in the region. Observations suggest that large patches of flowers are used more frequently and are much more important than widely distributed resources. Observations also indicate that the availability of suitable forage (nectar and pollen) sources throughout the whole season from May to September is crucial.

These resources need to be provided by an abundance of specific key forage sources, all of which significantly have very long flowering seasons as well as long corolla tubes which correspond to the long tongues of the bumblebees. Important plant species used in early summer by queens include Fodder Vetch Vicia villosa, Red Clover Trifolium pratense and Broad-leaved Everlasting-pea Lathyrus latifolius. Workers forage on the flowers of species such as bird?s-foot trefoils Lotus spp., clovers, Black Horehound Ballota nigra, Lucerne Medicago sativa and Red Bartsia Odondites verna (Harvey, 2000b; Harvey, 2001a). The UK Action Plan for the Brown-banded Carder Bee Bombus humilis states 'Where possible ensure that all occupied and nearby potential habitat is appropriately managed by 2008, for example through SSSI or agri-environment scheme management agreements' and 'Ensure that the habitat requirements of the species are taken into account in relevant development policies, plans and proposals.'